The invention relates to methods of and apparatus for checking the cylindricity of test surfaces, and more particularly to methods and apparatus of such type for checking the cylindricity of a plurality of axially spaced locations of the test surface.
Techniques are known for conveniently checking the degree of runout of a nominally cylindrical surface which is otherwise regular in configuration. The degree of runout of the cylindrical surface in such regular structures, which are characterized by a substantially linear axis, can be determined as a function of the difference between the largest and smallest diameter in a given diametral plane.
Far more complicated is the problem of measuring nonregular nominally cylindrical surfaces whose degree of runout and unevenness may vary in a non-linear manner in the axial direction, whereby the determination of the degree of non-cylindricity at one cross-sectional location is non-indicative in any way of the non-cylindricity at a spaced rotation.
In order to determine the non-cylindricity at such axially spaced locations. it has been necessary in the past to electronically record profilograms of the various surface contours of the spaced locations. Such techniques, of course, are complicated and expensive, and are furthermore time-consuming because of the necessity to analyze the recorded patterns.